In a Warming World Coastal Forests Are the Only Defense

As the world warms and oceans rise, coastal forests of mangrove, beach grasses, tupelo and bald cypress help protect coastlines from the ravages of hurricanes and typhoons. Unfortunately, even as these storms intensify due to climate change, coastal forests are being increasingly decimated by human activities ranging from oil production to shrimp or rice farming and tourism.

The end result of this alteration of the natural order can be seen in the aftermath of Hurricane Katrina in 2005 (New Orleans, Louisiana) and Cyclone Nargis in 2008 (Myanmar, the Irrawaddy Delta). These two episodes alone displaced more than four million people and killed nearly 150,000. The dollar loss is inestimable.

Much of this might have been prevented if natural ecosystems had not been altered. Mangroves, the most typical growth along coastlines, have deep, extensive, intertwining roots systems perfectly adapted to saline conditions and fluctuating water supplies, and bind the earth firmly against catastrophic storm surges.

A second line of coastal defense is provided by beach grasses, like papyrus or bulrushes, or sedge and wire grass. Further inland, where seawater becomes fresh water, there are savannah woodlands, dry forests, lowland rain forests, temperate and boreal forests and forest plantations. As a whole, these coastal plantations act to buffer storms, filter water, and provide habitat for a myriad of wildlife.

Many of these natural coastal defenses have been torn up, either to provide lumber or to make way for agriculture, fisheries or tourism. Where once a beach in Myanmar ran hundreds of feet deep with mangrove swamps, harboring everything from white-shouldered ibis to crocodiles and sea turtles, that same beach today is likely either a shrimp farm or a tourist resort. In the latter case, Nature has been carefully resculpted with pretty trees and white sand beaches that appeal esthetically but do nothing to dampen a cyclone’s force.

A similar situation exists in Louisiana, where agriculture has mandated “engineered” rivers and river channels that eliminate Gulf silt deposits and reduce the land by 25 square miles every successive year. Runoff from farms along the Mississippi brings in fertilizer residue, and eutrophication at the mouth of the Gulf has created a New-Jersey sized dead zone where nothing can survive, even “junk” fish no one is willing to eat. Yet the U.S. Army Corps of Engineers wants to put in more channels, pumps and floodgates, and approves every permit for wetland destruction put before it.

A newer threat to the Gulf and its wetlands is suspension of a former moratorium on offshore drilling, which will lead to booming oil and gas exploration. The ensuing intentional discharges of heated water (and accidental discharges of fossil fuels) will further destroy fragile and rapidly disappearing ecosystems.

Truth be told, manmade flood-control systems don’t work. They help us extract oil and gas, ship goods, plant crops and build resorts, but they don’t protect the land – the essence from which all other blessings flow. Native wetlands act as “speed bumps” for bad weather. Storm waters lose their energy fighting the mass and meshed roots of mangrove swamps, with their dense packets of bulrushes and other sea grasses. In fact, one study demonstrated that every two miles of contiguous wetlands diminishes the height of a hurricane-driven wave by up to a foot. In Louisiana, where losses are upwards of 40 square miles of marsh per year, the sea has advanced 20 miles inland in the last half century.

Some efforts are being made to reverse these losses. In Florida, a new program is underway to restore the seagrass in one part of Florida Keys National Marine Sanctuary. The Nature Conservancy has, for the last four decades, been working to restore more than two dozen sites around the Gulf of Mexico, including sustainable forests, grasslands, marshes and coastal areas.

Unfortunately, restoration is a perilous and painstaking process further hampered by the increasing rate and intensity of storms, rising sea levels, sinking cities and budgetary shortfalls. These setbacks means much work may not be done, or undone by the next big hurricane in a matter of hours.

My father had a wonderful saying: “That which is begun in desperation ends in failure.” In our haste to remake the natural world into an image that more suits our tastes and endeavors, we have opened ourselves up to greater losses (of life, money and time) than if we had simply worked with Nature. Our efforts now may be too late.